Electoless Nickel

Electroless Nickel

  • Electroless Nickel (EN) is an autocatalytic plating process which does not require rectifiers, electrical current or anodes.
  • One of the distinct advantages aside from excellent wear and corrosion resistance is the uniformity of plating on all areas of part being plated. Slots, grooves, blind holes, threads, and even the inside of a cylinder will have the same thickness of coating. This will eliminate some post finishing operations resulting in lowered overall finishing costs.
  • EN is an amorphous alloy of nickel and phosphorous or Boron or cobalt. By varying the percentage of above and adding composites like Teflon (PTFE) provide different functional coatings that have their own unique properties.
  • EN can be replaced for a Hard Chrome plating in certain applications

General Functional Properties:

  • Corrosion Resistance
  • Wear Resistance
  • Hardness
  • Lubricity
  • Solderability and bondability
  • Uniformity of deposit regardless of geometries
  • Nonmagnetic properties of high phosphorous alloy

Electroless Nickel Plating can be covered by the following specifications:

  • AMS 2404C, Electroless Nickel Plating (Replaces MIL-C-26074)
  • AMS 2405B, Electroless Nickel Plating, Low Phosphorus
  • ASTM B656, Standard Guide for Autocatalytic Nickel-Phosphorus Deposition on Metals for Engineering Use
  • ASTM B733, Standard Specification for Autocatalytic Nickel-Phosphorus Coatings on Metal (Replaces MIL-C-26074)
Service Condition. The severity of the environment is presented here.
SC4: Very severe service Coating thickness 60 µm minimum
SC3: Severe service Coating thickness 30 µm minimum
SC2: Moderate service Coating thickness 13 µm minimum
C1: Mild service, solderings Coating thickness five µm minimum

Test Types. The test type defines which tests should be performed.

Type I: Appearance, thickness, adhesion, porosity
Type II: Includes Type I and hardness
Type III: Includes Type I and alloy composition

Post Treatment. Classes of post heat treatment are referenced:
Class 1: As deposited Class 2: 850 Knoop hardness minimum
Class 3: Heat treat at 180 to 200C for two to four hours to improve adhesion and provide hydrogen embrittlement relief.
Class 4: Heat treat at 120 to 130C for at least one hour to improve adhesion on heat-treatable aluminum alloys and carburized steel
Class 5: Heat treat at 140 to 150C for at least one hour to improve adhesion for non-age-hardened aluminum and beryllium alloys